I doubt you will sink, but it sounds like it is time to replace that mess with an actual seacock (i.e., not a thru-hull with an attached ball valve). Remember thru-hulls have straight threads while ball valves generally have tapered threads. That ball valve is likely only engaging 3-5 threads on the thru-hull.
I doubt you will sink, but it sounds like it is time to replace that mess with an actual seacock (i.e., not a thru-hull with an attached ball valve). Remember thru-hulls have straight threads while ball valves generally have tapered threads. That ball valve is likely only engaging 3-5 threads on the thru-hull.
Seacock & Thru-Hull Primer/Pre Information Photo Gallery by Compass Marine How To at pbase.comI doubt you will sink, but it sounds like it is time to replace that mess with an actual seacock (i.e., not a thru-hull with an attached ball valve). Remember thru-hulls have straight threads while ball valves generally have tapered threads. That ball valve is likely only engaging 3-5 threads on the thru-hull.
Tdunn is right, replace those with real seacocks next time you haul.
Another option would be to use a Groco flanged adapter between the thru-hull and ball valve.
Is there a backing block or are those mounted directly to the hull? If no backing blocks, add them.
I doubt you will sink, but it sounds like it is time to replace that mess with an actual seacock (i.e., not a thru-hull with an attached ball valve). Remember thru-hulls have straight threads while ball valves generally have tapered threads. That ball valve is likely only engaging 3-5 threads on the thru-hull.
Generator is also a ball valve on the thru-hull. You have an actual seacock on the main engine intake. I always wonder why builders install ball valves considering the thread mismatch. I guess it is to save a few bucks since a seacock costs 2-3 times what a ball valve costs. It is possible to mount a seacock without a thru-hull, although I always use one.
That first picture is of a marine ball valve. See the drain plug in the lower right- that indicates a marine thru hull ball valve. These valves have straight threads on the bottom to screw in to the straight pipe thread on the thru hull and tapered threads on the top. There is nothing wrong with these, but integral flanged seacocks are stronger.
That slop that you feel is normal. There is a stem that fits in to the ball with a socket. It is designed to have a little slop.
David
Before the sky actually falls...
I did have some previous discussion with Buck Algonquin about the threads on their seacocks and ball valves... and their tech told me they purposely cut the leading threads so their NPT ball valves will attach securely to an NPS thru hull. Groco literature, somewhere down in the fine print, suggests the same.
Near as I can remember, I've never owned a boat with flanged seacocks. None have sunk, or even leaked.
Not suggesting this is good practice, just adding perspective...
-Chris
So if some Buck Algonquin phone guy told you their valves have straight threads on the input end all I can say is that their technical specifications on the web site say the valves are all 100% tapered (NPT) threads.
So looking at these pictures, can I leave the existing through hull in place and just install the flange and a new valve?
How does that flange bolt to the hull?
So looking at these pictures, can I leave the existing through hull in place and just install the flange and a new valve?
How does that flange bolt to the hull?
Chris, the only combination threads I've seen were on a stainless thru-hull and I can't remember who made it. I read Groco's instructions for installing Seacocks and In-line valves on thru-hulls. (with flange it's a seacock, without flange it's an inline valve). The instructions do talk about combination threads but I don't think Groco (or Buck) thru-hulls have combination threads. I'll ask Groco about it and let you know what I find out.
Cardude, I suggest that you use the Groco premade backing plates and the Groco flanged adapters. Inspect and clean your existing ball valves and thru-hull fittings. if they look ok, reuse them.
The backing plates are usually glued to the hull with epoxy. they have threaded inserts to which the flange is bolted.
Cardude, I suggest that you use the Groco premade backing plates and the Groco flanged adapters. Inspect and clean your existing ball valves and thru-hull fittings. if they look ok, reuse them.
The backing plates are usually glued to the hull with epoxy. they have threaded inserts to which the flange is bolted.
Chris, the only combination threads I've seen were on a stainless thru-hull and I can't remember who made it. I read Groco's instructions for installing Seacocks and In-line valves on thru-hulls. (with flange it's a seacock, without flange it's an inline valve). The instructions do talk about combination threads but I don't think Groco (or Buck) thru-hulls have combination threads. I'll ask Groco about it and let you know what I find out.
The thru-hull that I saw with combination thread had a definite taper over about the last inch of thread. It was very obvious.